KR20140008610A - Apparatus and method of transmitting ue mobility index - Google Patents

Abstract

The present invention relates to an apparatus and a method for transmitting a mobility indicator of a terminal.
The present specification includes the steps of checking the mobility of the terminal based on the number of cell changes, transmitting a mobility indicator indicating the mobility of the checked terminal to the base station, and the radio resource control reconfigured by the base station based on the mobility indicator A method of transmitting a mobility indicator, the method comprising: receiving an RRC connection reconfiguration message including a parameter of a (RRC) layer from the base station, and configuring a parameter of the RRC layer in the terminal.
According to the present invention, a process of transmitting mobility-related information by the terminal to the base station becomes clear, and all terminals always transmit mobility indicators, thereby preventing a problem that the base station needs to receive the mobility indicators unnecessarily.

Description

Apparatus and method for transmitting mobility indicator of terminal {APPARATUS AND METHOD OF TRANSMITTING UE MOBILITY INDEX}

The present invention relates to wireless communication, and more particularly, to an apparatus and method for transmitting a mobility indicator of a terminal.

3rd generation partnership project (3GPP) long term evolution (LTE), an improvement of the Universal Mobile Telecommunications System (UMTS), uses orthogonal frequency division multiple access (OFDMA) multiplexing in downlink, and single carrier SC-FDMA in uplink -frequency division multiple access) Use multiplexing. Recently, 3GPP LTE-A (LTE-Advanced), an evolution of 3GPP LTE, is under discussion.

The layers of the radio interface protocol between the user equipment (UE) and the network are based on the lower three layers of the Open System Interconnection (OSI) model, which is well known in communication systems. The first layer (L1), the second layer (L2), the third layer (L3) may be divided into a physical layer belonging to the first layer (information transfer service) using a physical channel (physical channel) The physical layer belonging to the first layer provides an information transfer service using a physical channel, and the RRC (Radio Resource Control) layer located in the third layer includes: It controls radio resources between networks.

The RRC state of the terminal is defined as whether or not the RRC layer of the terminal is in logical connection with the RRC layer of the Evolved-UMTS Terrestrial Radio Access Network (E-UTRAN). When connected, it is called RRC connected state, and when not connected, it is called RRC idle state. Since the RRC-connected terminal has an RRC connection, the E-UTRAN can grasp the existence of the corresponding terminal on a cell-by-cell basis, thereby effectively controlling the terminal. On the other hand, the terminal of the RRC idle state is not identified by the E-UTRAN and managed by the core network in units of a tracking area, which is a larger area unit than the cell. That is, the presence of the terminal in the RRC idle state is identified only in a large area unit, and must move to the RRC connected state in order to receive a normal mobile communication service such as voice or data.

Mobile communication systems such as LTE or LTE-A should support the mobility (mobility) of the terminal. For example, in a cell-based mobile communication system, handover, cell selection, or cell reselection may be performed when the UE moves from cell to cell to ensure mobility. Can be. Handover is performed when the UE moves in the RRC connected state, and cell selection or cell reselection is performed when the UE moves in the RRC idle state. The mobility state of the terminal may be used to appropriately set various parameters required for communication with the terminal.

For example, when performing a measurement in the RRC layer of the terminal, the terminal scales a parameter value related to the measurement based on the moving speed of the terminal. The reason why the terminal measures the speed is because the speed of the terminal is used to scale Q _hyst , T _reselection , and time to trigger (TTT), which are cell change parameters. Alternatively, when the base station or the terminal determines handover, cell selection, or cell reselection, information on the speed of the terminal may be used. Therefore, the terminal estimates and collects the moving state of the terminal such as speed. In order for the collected information on the mobility of the terminal to be used at the time of cell selection or handover, the base station should acquire information about the mobility of the terminal. To this end, the definition of information on mobility and the procedure for exchanging information on mobility between the terminal and the base station should be clearly defined.

An object of the present invention is to provide an apparatus and method for transmitting a mobility indicator of a terminal.

Another technical problem of the present invention is to provide a method for notifying a terminal whether a base station supports reception of a mobility indicator.

Another technical problem of the present invention is to provide a method for a terminal to check mobility indicators.

Another technical problem of the present invention is to provide an apparatus and method for exchanging mobility indicators by a terminal performance procedure.

According to an aspect of the present invention, there is provided a mobility support method of a terminal performed by a terminal. The method may include checking mobility of a terminal based on the number of cell changes, transmitting a mobility index indicating a mobility of the checked terminal to a base station, and checking the mobility index. Receiving an RRC connection reconfiguration message from the base station, the RRC connection reconfiguration message including parameters of a radio resource control (RRC) layer reconstructed by the base station, and configuring parameters of the RRC layer in the terminal.

According to another aspect of the present invention, a method of supporting mobility of a terminal performed by a base station is provided. The method includes receiving a mobility index indicating a mobility of the terminal, and a parameter of a radio resource control (RRC) layer set up in the terminal using the mobility index. Reconfiguring a message, and transmitting an RRC connection reconfiguration message including parameters of the reconfigured RRC layer to the terminal.

According to another aspect of the present invention, a terminal for transmitting a mobility indicator is provided. The terminal may include a mobility checker that checks mobility of the terminal based on the number of cell changes, a transmitter that transmits a mobility index indicating a mobility of the checked terminal to a base station; A receiver configured to receive an RRC connection reconfiguration message including parameters of a radio resource control (RRC) layer reconstructed by the base station based on a mobility indicator, and a message processor configured to configure the parameters of the RRC layer in the terminal; do.

According to still another aspect of the present invention, there is provided a base station supporting mobility of a terminal. The base station includes a receiver for receiving a mobility index indicating mobility of the terminal and a parameter of a radio resource control (RRC) layer set up in the terminal using the mobility index. A parameter change unit configured to reconfigure the message, a message processor configured to generate an RRC connection reconfiguration message including the reconfigured RRC layer parameters, and a transmitter configured to transmit the RRC connection reconfiguration message to the terminal. .

By indexing the mobility of the terminal, the process of transmitting the mobility-related information to the base station can be clear. Since all terminals always transmit mobility indicators, a problem that the base station needs to receive mobility indicators unnecessarily can be prevented. Furthermore, the signaling congestion of the network can be reduced by allowing the terminal to transmit the mobility indicator to the base station only through the terminal allowed through the mobility support information.

1 shows a wireless communication system to which the present invention is applied.
2 is an exemplary diagram illustrating a process of performing cell selection or cell reselection by a UE in an RRC idle state according to the present invention.
3 is a flowchart illustrating a method of supporting mobility of a terminal according to an embodiment of the present invention.
4 is a conceptual diagram illustrating a DRX related parameter and a DRX operation reconfigured based on a mobility indicator according to an embodiment of the present invention.
5 is a flowchart illustrating a method of supporting mobility of a terminal according to another example of the present invention.
6 is a flowchart illustrating a method of supporting mobility of a terminal according to another embodiment of the present invention.
7 is a flowchart illustrating a method of supporting mobility of a terminal according to another embodiment of the present invention.
8 is a flowchart illustrating a method of supporting mobility of a terminal according to another embodiment of the present invention.
9 is an operation flowchart of a terminal supporting mobility of the terminal according to an embodiment of the present invention.
10 is a flowchart illustrating an operation of a base station supporting mobility of a terminal according to an embodiment of the present invention.
11 is a block diagram illustrating a terminal and a base station supporting mobility of the terminal according to an embodiment of the present invention.

Hereinafter, the contents related to the present invention will be described in detail with reference to exemplary drawings and embodiments, together with the contents of the present invention. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In addition, in describing the embodiments of the present specification, when it is determined that the detailed description of the related well-known configuration or function may obscure the subject matter of the present specification, the detailed description thereof will be omitted.

In addition, the present invention will be described with respect to a wireless communication network. The work performed in the wireless communication network may be performed in a process of controlling a network and transmitting data by a system (e.g., a base station) Work can be done at a terminal connected to the network.

According to embodiments of the present invention, 'transmitting a control channel' can be interpreted as meaning that control information is transmitted through a specific channel. Here, the control channel may be, for example, a physical downlink control channel (PDCCH) or a physical uplink control channel (PUCCH).

1 shows a wireless communication system to which the present invention is applied. This may be referred to as Evolved-UMTS Terrestrial Radio Access Network (E-UTRAN) or Long Term Evolution (LTE) / LTE-A system.

1, an E-UTRAN includes a base station (BS) 20 providing a control plane and a user plane to a user equipment (UE) . The terminal 10 may be fixed or mobile and may be referred to by other terms such as a mobile station (MS), a user terminal (UT), a subscriber station (SS), a mobile terminal (MT) . The base station 20 refers to a station that communicates with the terminal 10 and may be called by other terms such as an evolved-NodeB (eNB), a base transceiver system (BTS), an access point, and the like.

The base stations 20 may be connected to each other through an X2 interface. The base station 20 is connected to a Serving Gateway (S-GW) through an MME (Mobility Management Entity) and an S1-U through an Evolved Packet Core (EPC) 30, more specifically, an S1-MME through an S1 interface. The S1 interface exchanges OAM (Operation and Management) information to support the movement of the terminal 10 by exchanging signals with the MME.

The EPC 30 is composed of an MME, an S-GW, and a P-GW (Packet Data Network-Gateway). The MME has information on the connection information of the terminal 10 and the capability of the terminal 10. This information is mainly used for managing the mobility of the terminal 10. [ The S-GW is a gateway having an E-UTRAN as an end point, and the P-GW is a gateway having a PDN as an end point.

Layers of the Radio Interface Protocol between the terminal 10 and the network are based on the lower three layers of the Open System Interconnection (OSI) reference model, which is widely known in communication systems. Layer), L2 (second layer), and L3 (third layer), among which the physical layer belonging to the first layer provides an information transfer service using a physical channel. The RRC (Radio Resource Control) layer located in the third layer plays a role of controlling radio resources between the terminal 10 and the network. To this end, the RRC layer exchanges RRC messages between the UE 10 and the BS.

A physical layer (PHY) layer provides an information transfer service to a higher layer by using a physical channel. The physical layer is connected to a medium access control (MAC) layer belonging to a second layer through a transport channel. Data is transferred between the MAC layer and the physical layer through the transport channel. The transport channel is classified according to how the data is transmitted through the air interface.

Data moves through a physical channel between the physical layer of the transmitter and the physical layer of the receiver. The physical channel is modulated by orthogonal frequency division multiplexing (OFDM) or single carrier-frequency division multiple access (SC-FDMA), and utilizes time and frequency as radio resources.

The functions of the MAC layer are to map a logical channel to a transport channel, to perform a hybrid automatic repeat request (HARQ) transmission, to transmit a MAC control element (CE), to perform a random access procedure, And performing a discontinuous reception (DRX) operation.

Functions of the RLC layer belonging to the second layer include concatenation, segmentation, and reassembly of the RLC SDUs. The RLC layer includes a Transparent Mode (TM), an Unacknowledged Mode (UM), and an Acknowledged Mode (RB) in order to guarantee various QoSs required by a radio bearer (RB) , And AM). AM RLC provides error correction via automatic repeat request (ARQ).

The functions of the Packet Data Convergence Protocol (PDCP) layer in the user plane include transmission of user data, header compression and ciphering. The function of the Packet Data Convergence Protocol (PDCP) layer in the user plane includes transmission of control plane data and encryption / integrity protection.

A radio resource control (RRC) layer belonging to the third layer performs configuration, re-configuration, and release of radio bearers (RBs), logical channels, transport channels, and physical channels. Take charge of their control. RB means a logical path provided by the first layer (PHY layer) and the second layer (MAC layer, RLC layer, PDCP layer) for data transmission between the terminal 10 and the network. The setting of the RB means a process of defining characteristics of a radio protocol layer and a channel to provide a specific service, and setting each specific parameter and an operation method. RB can be divided into SRB (Signaling RB) and DRB (Data RB). The SRB is used as a path for transmitting the RRC message in the control plane, and the DRB is used as a path for transmitting the user data in the user plane.

When there is an RRC connection between the RRC layer of the UE 10 and the RRC layer of the E-UTRAN, the UE 10 is in an RRC CONNECTED state. If not, the RRC IDLE ) State.

The downlink transport channel for transmitting data from the network to the terminal 10 includes a BCH (Broadcast Channel) for transmitting system information and a downlink shared channel (SCH) for transmitting user traffic or control messages. In case of a traffic or control message of a downlink multicast or broadcast service, it may be transmitted through a downlink SCH, or may be transmitted via a separate downlink MCH (Multicast Channel). Meanwhile, the uplink transport channel for transmitting data from the terminal 10 to the network includes a random access channel (RACH) for transmitting an initial control message and an uplink shared channel (SCH) for transmitting user traffic or control messages. have.

It is located above the transport channel, and the logical channel mapped to the transport channel is a broadcast control channel (BCCH), a paging control channel (PCCH), a common control channel (CCCH), a multicast control channel (MCCH), and a multicast traffic (MTCH). Channel, downlink-shared channel (DL-SCH) and the like.

Hereinafter, the RRC state (RRC state) and the RRC connection method of the UE will be described in detail.

The RRC state refers to whether or not the RRC layer of the UE is in logical connection with the RRC layer of the E-UTRAN. If connected, the RRC connection state is referred to; Call. Since the RRC-connected terminal has an RRC connection, the E-UTRAN can grasp the existence of the corresponding terminal on a cell-by-cell basis, thereby effectively controlling the terminal. On the other hand, the terminal of the RRC idle state is not identified by the E-UTRAN and managed by the core network in units of a tracking area, which is a larger area unit than the cell. That is, the presence of the terminal in the RRC idle state is identified only in a large area unit, and must move to the RRC connected state in order to receive a normal mobile communication service such as voice or data.

The UE searches for the appropriate cell of the Public Land Mobile Network (PLMN) and stays in the RRC idle state in the cell. The UE in the RRC idle state selects a cell capable of providing possible services and adjusts to the control channel of the selected cell. This process is called "camp on a cell." When camping is completed, the terminal may register its presence in the registration area of the selected cell. This is called location registration (LR). The terminal registers its presence in the registration area regularly or enters a new tracking area (TA). The registration area refers to any area where the terminal may roam without a location registration procedure.

If the terminal leaves the service area of the cell or finds a more suitable cell, the terminal reselects and camps the most suitable cell in the PLMN. If a new cell is included in another registration area, a location registration request is performed. If the terminal moves out of the service area of the PLMN, a new PLMN may be automatically selected or a new PLMN may be manually selected by the user.

The purpose of proceeding camp on the terminal of the RRC idle state is as follows.

1) UE receives system information from PLMN, 2) UE initially accesses network through control channel of camped cell after initializing call, 3) Receive paging message: PLMN When receiving a call for this terminal, the PLMN knows the registration area of the cell camped on. Therefore, the PLMN can send a paging message for the terminal through the control channel of all cells in the registration area. The terminal may receive a paging message because the terminal is already adjusted for the control channel of the camped cell. 4) Receive a broadcasting message of the cell.

If the terminal cannot find a suitable cell to camp on, or if a subscriber identity module (SIM) card is not inserted or if a specific response to a location registration request is received (for example, an "illegal terminal"), the terminal is connected to the PLMN. Regardless, try to camp on and enter the "limited service" state. The limited service state is an emergency call only state.

When the power is turned on or remains in the cell, the terminal performs procedures for selecting and reselecting an appropriate quality cell to receive the service.

The UE in the RRC dormant state should always select a cell of appropriate quality and prepare to receive service through this cell. For example, a powered down terminal must select a cell of the appropriate quality to register with the network. When the UE in the RRC connected state enters the RRC idle state, the terminal should select a cell to stay in the RRC idle state. As such, the process of selecting a cell satisfying a certain condition in order for the UE to stay in a service standby state such as an RRC idle state is called cell selection. Importantly, cell selection is performed in a state in which the UE has not currently determined to be in the RRC idle state, so it is most important to select the cell as quickly as possible. Therefore, even if the cell provides the best radio signal quality to the UE, it can be selected in the cell selection process of the UE.

There are two main cell selection processes.

One is an initial cell selection process, in which the UE does not have prior information on the radio channel. Therefore, the terminal searches all radio channels to find an appropriate cell. In each channel, the terminal finds the strongest cell. Thereafter, the terminal selects a corresponding cell if it finds a suitable cell that satisfies the cell selection criteria.

The other is a cell selection process using stored information. In this process, cell selection is performed by using information stored in a terminal for a wireless channel or by using information broadcast in a cell. Therefore, the cell selection can be faster than the initial cell selection process. If the terminal finds a cell satisfying the cell selection criterion, the cell is selected. If a suitable cell that satisfies the cell selection criteria is not found through this process, the UE performs an initial cell selection process.

2 is an exemplary diagram illustrating a process of performing cell selection or cell reselection by a UE in an RRC idle state according to the present invention.

Referring to FIG. 2, the terminal selects a PLMN and a radio access technology (RAT) to be serviced (S210). The PLMN and RAT may be selected by the user of the terminal or may use the one stored in the USIM.

The terminal selects a cell having the largest value among the measured base station and a cell whose signal strength or quality is greater than a specific value (S220). This is an initial cell selection process. The terminal receives system information periodically transmitted by the base station. A specific value is a value defined in the system to ensure the quality of a physical signal in data transmission / reception. Therefore, the value may vary depending on the applied RAT.

The cell selection criterion used by the terminal in the cell selection process is shown in Equation 1 below.

Here, Srxlev = Q _rxlevmeas- (Q _rxlevmin + Q _{rxlevminoffset} ) + Pcompensation. Q _rxlevmeas is the reception level of the measured cell (RSRP), Q _rxlevmin is the minimum required reception level (dBm) in the cell, Q _{rxlevminoffset} is the offset for Q _rxlevmin , Pcompensation = max (P _EMAX -P _UMAX , 0 (dB), P _EMAX is the maximum transmit power (dBm) that the terminal can transmit in the cell, P _UMAX is the maximum transmit power (dBm) of the terminal radio transmitter (RF) according to the performance of the terminal.

In Equation 1, the UE can know that the strength and quality of the measured signal selects a cell larger than a specific value determined by the cell providing the service. In addition, parameters used in Equation 1 are broadcast through system information, and the terminal receives these parameter values and uses them in cell selection criteria.

When the terminal selects a cell that satisfies the cell selection criteria, the terminal receives information necessary for the RRC idle state operation of the terminal in the cell from the system information of the cell. After the UE receives all the information necessary for the RRC idle state operation, the UE waits in the idle mode to request a service (eg, an originating call) or to receive a service (eg, a terminating call) from the network.

That is, if a network registration is required, the terminal registers its information (eg IMSI) in order to receive a service (eg paging) from the network (S230 and S240). The terminal does not register in the network to which it is connected every time a cell is selected. For example, if the system information of the network to be registered (for example, Tracking Area Identity (TAI)) is different from the information of the network known to the user, the network is registered in the network.

If the value of the strength or quality of the signal measured from the base station being served is lower than the value measured from the base station of the adjacent cell, the terminal selects another cell that provides better signal characteristics than the cell of the base station to which the terminal is connected ( S250). This is because, after the terminal selects a cell through a cell selection process, the strength or quality of the signal between the terminal and the base station may change due to the mobility of the terminal or a change in the wireless environment. This process is referred to as cell reselection, distinguished from initial cell selection in step S220. If the quality of the selected cell is degraded, the terminal may select another cell that provides better quality. In this case, a time constraint may be set in order to prevent the cell from being frequently reselected according to the change of the signal characteristic. The cell reselection process has a basic purpose in terms of quality of a radio signal, in general, to select a cell that provides the best quality to the terminal.

The terminal may select the initial cell as in step S220 or increase the number of cell selection by 1 each time the cell is reselected as in step S250. The cumulative number of cell selections may be converted into a kind of index (reduced as a mobility index) for measuring the mobility of the terminal. This is because the cumulative number of cell selections during the unit time may mean how many cells the terminal has moved in a given unit time. The terminal may check or estimate mobility of the terminal based on the number of cell selections. For example, if the number of cell selections accumulated during the unit time is relatively large, it is assumed that the terminal is moving at high speed. Therefore, the terminal determines the mobility indicator as 'high speed'. On the other hand, if the number of cell selections accumulated during the unit time is relatively small, it is assumed that the terminal is moving at a low speed. Accordingly, the terminal determines the mobility indicator as 'low speed'. On the other hand, since it may be ambiguous to relatively determine the mobility of the terminal from the number of cell selections, a threshold number may be used to more accurately map the number of cell selections and the mobility of the terminal.

The terminal checks whether the number of cell selections reaches a predetermined threshold number within a unit time. For example, if the number of cell selections is checked to reach a predefined threshold number within a unit time, the mobility of the terminal is estimated to correspond to a high speed. Therefore, the terminal determines the mobility indicator as 'high speed'. On the other hand, if the number of cell selections does not reach a predefined threshold number within a unit time, the mobility of the terminal is estimated to correspond to a low speed. Accordingly, the terminal determines the mobility indicator as 'low speed'.

Of course, this is disclosed for illustrative purposes, and the mobility of the terminal does not necessarily correspond to two speed states such as high speed and low speed, and may correspond to three speed states such as high speed, medium speed, and low speed. Of course, it can correspond to the speed state.

In addition, it can be converted into a mobility index (mobility index) of the terminal is various. For example, the terminal may directly measure or check a moving speed of the terminal in RRC idle state by various means. The terminal may divide the speed of the terminal directly measured into several sections and use the terminal as an indicator of mobility. As an example, the speed range is 0 to 30 km / h (0 to 8.3 m / s), 30 to 60 km / h (8.3 to 16.6 m / s), 60 to 120 km / h (16.6 to 33.2 m / s), and each section may correspond to a mobility index divided into low speed, medium speed, and high speed. For example, 0 to 30 km / h (0 to 8.3 m / s) at low speed, 30 to 60 km / h (8.3 to 16.6 m / s) at medium speed, 60 to 120 km / h (16.6 to 33.2) m / s) corresponds to high speed. In this way, the terminal can check the mobility of the terminal. Of course, this is only an example, and the mobility index corresponding to each speed interval may be defined differently by the mobile operator or the terminal manufacturer.

By indicating the mobility of the terminal in this way, the terminal can clearly inform the mobility of the terminal to the base station.

The reason for obtaining the mobility indicator of the terminal is that the mobility indicator of the terminal is used to scale cell change parameters Q _hyst , T _reselection , and time to trigger (TTT). The cell change parameter is control information used to reduce cell change failure when the UE performs cell change from the current cell to another cell. Q _hyst is a value that adds or subtracts a value indicating the good or bad state of the radio state of the current cell, and controls the good or bad of the radio state relative to the new cell. T _reselection is a time during which a new cell must maintain a radio state superior to a current cell in order for the idle mode terminal to _{reselect a} new cell. When the radio state of the new cell becomes a certain reference value or more than the current cell and the radio state is maintained for the trigger time, the UE starts a measurement report in a handover preparation step such as a measurement report. The parameter used to enter.

For example, if the speed of the UE in the idle mode is high speed, the UE scales to reduce the T _reselection and Q _hyst values so that the cell _reselection can be performed quickly, and if the speed is low, the UE _{resizes the} T _reselection and Q _hyst values. Scale to grow larger. The base station informs the terminal of scaling factors corresponding to each speed level so that the terminal can scale T _reselection , Q _hyst , and trigger time according to the speed of the terminal.

3 is a flowchart illustrating a method of supporting mobility of a terminal according to an embodiment of the present invention.

Referring to Figure 3, the terminal checks the mobility of the terminal (S300). At this time, the UE is in an RRC idle state. The terminal may estimate, measure, or determine the mobility of the terminal by various methods.

As an example, the terminal may check the mobility of the terminal based on the number of cell selections. For example, the mobility check of the terminal increases the number of cell selections by 1 each time the terminal selects an initial cell as in step S220 or reselects a cell as in step S250, and increases the number of cell selections accumulated in a unit time. Accordingly, may include determining a mobility indicator of the terminal. If the number of cell selections accumulated during the unit time is relatively large, it is assumed that the terminal is moving at high speed. Therefore, the terminal determines the mobility indicator as 'high speed'. On the other hand, if the number of cell selections accumulated during the unit time is relatively small, it is assumed that the terminal is moving at a low speed. Accordingly, the terminal determines the mobility indicator as 'low speed'.

In more detail, the mobility check of the terminal includes the terminal checking whether the number of cell selections reaches a predetermined threshold number within a unit time. If the number of cell selections is checked to reach a predefined threshold number within a unit time, the mobility of the terminal is estimated to correspond to high speed. Therefore, the terminal determines the mobility indicator as 'high speed'. On the other hand, if the number of cell selections does not reach a predefined threshold number within a unit time, the mobility of the terminal is estimated to correspond to a low speed. Accordingly, the terminal determines the mobility indicator as 'low speed'. In other words, if the cell selection is counted more than a certain number of times within a unit time, the terminal is classified as a high speed terminal, and if it is counted less than a certain number of times, the terminal is classified as a low speed terminal. Can be. Alternatively, if the cell selection has an intermediate number of times within a unit time, it may be classified as a middle speed terminal.

As another example, the terminal may check the mobility of the terminal based on the actual measurement speed. In other words, the UE may directly measure or check the speed at which the UE moves in the RRC idle state by various means. The terminal may divide the speed of the terminal directly measured into several sections and use the terminal as an indicator of mobility. For example, the speed ranges from 0 to 30 km / h (0 to 8.3 m / s), 30 to 60 km / h (8.3 to 16.6 m / s), and 60 to 120 km / h (16.6 to 33.2 m / s), and each section may correspond to a mobility index divided into low speed, medium speed, and high speed. If the speed of the terminal directly measured by the terminal is 35 km / h, this corresponds to the middle speed section, and thus the terminal determines the mobility index of the terminal as 'middle speed'.

The terminal generates a mobility indicator corresponding to the mobility of the checked terminal (S305). The mobility indicator of the terminal may be expressed in various forms. As an example, the terminal may indicate the number of cell selections of the terminal itself as a mobility indicator. For example, if the number of cell selections of the terminal is 5 for a unit time, the terminal displays as follows: mobility indicator = 5. The mobility indicator is then indicated in the form of an integer.

As another example, the terminal may indicate the speed itself at which the terminal moves as a mobility indicator. For example, if the speed of the terminal directly measured by the terminal is 35 km / h, the terminal may display the mobility indicator = 35 km / h.

As another example, the terminal may indicate a level of the moving speed as a mobility indicator, such as 'mobility indicator = high speed' or 'mobility indicator = low speed'. For example, if the speed level is defined in only two types, high speed and low speed, the terminal may define the mobility indicator as 1-bit information. If the mobility indicator is 1, the high speed may be indicated, and if the mobility indicator is 0, the low speed may be indicated. have. In the case of indicating other additional information such as medium speed, the mobility indicator may be defined as 2-bit information. For example, if the mobility index is 00, the movement speed is 0; if the mobility index is 01, the movement speed is high; if the mobility indicator is 10, the movement speed is medium speed; if the mobility indicator is 11, the movement speed is low. Can be. The representation form may be variably defined.

The terminal may generate the mobility indicator by using any one of various methods of representing the mobility indicator as described above. In order to secure the latest mobility index required by the base station, the terminal may maintain the mobility index through data within a predetermined time.

The terminal transmits the generated mobility indicator to the base station (S310). The mobility indicator may be transmitted not only by higher layer signaling such as an RRC message but also by lower layer signaling such as a MAC layer or a physical layer. As a result, the process of transmitting mobility-related information from the terminal to the base station may be clear.

The base station receives the generated mobility indicator, and reconfigures the RRC-related parameters of the terminal based on the received mobility indicator. The RRC related parameters may include those affected by mobility of the terminal, for example, DRX operation parameters. Alternatively, the RRC related parameter affected by the mobility of the terminal may include a connection release timer. Alternatively, the RRC related parameters affected by the mobility of the terminal may include radio resource configuration or reconfiguration. Modification or reconfiguration of RRC-related parameters includes radio resource configuration or radio resource reconfiguration.

4 is a conceptual diagram illustrating a DRX related parameter and a DRX operation reconfigured based on a mobility indicator according to an embodiment of the present invention.

Referring to FIG. 4, the DRX operation is repeated in units of a DRX cycle (400). The DRX cycle 400 is a periodic repetition of an on duration 405 following an inactive section. Is defined. One cycle of the DRX cycle 400 includes a duration 405 and a DRX opportunity for DRX 410. The RRC layer manages several timers to control the DRX operation. The timers controlling the DRX operation include a duration timer (onDurationTimer), a DRX inactivity timer (drxInactivity Timer), and a DRX retransmission timer (drxRetransmission Timer).

Including the duration of the duration timer or the DRX inactivity timer or the DRX retransmission timer is called active time. Alternatively, the activity time may mean all sections in which the UE can monitor the PDCCH. When the DRX cycle 400 is configured, the activity time includes the duration of the duration timer or the DRX inactivity timer or the DRX retransmission timer. The terminal monitors the PDCCH for the PDCCH subframe (PDCCH subframe) during the active time. If the terminal has a DRX parameter configured in the RRC connection state, the terminal performs discontinuous monitoring on the PDCCH based on the DRX operation. On the other hand, if the DRX parameter is not configured, the UE performs continuous PDCCH monitoring. Discontinuous PDCCH monitoring may mean that the UE monitors the PDCCH only in a specific subframe, and continuous PDCCH monitoring may mean that the UE monitors the PDCCH in all subframes. On the other hand, when PDCCH monitoring is required in a DRX-independent operation such as a random access procedure, the UE monitors the PDCCH according to the requirements of the corresponding operation.

In other words, DRX refers to a function that enables the UE to stop monitoring the PDCCH for a predetermined period (ie, sleep period or inactive time), and the UE wakes up with a certain periodicity in the DRX mode. Repeat the wake up or active and sleep or non-active or inactive periods. Wake up (or activity) means to monitor the PDCCH. Sleep (or inactivity) means stopping monitoring the PDCCH. The DRX may be configured by radio resource control / media access control (RRC / MAC).

In addition, DRX operation parameters include a long DRX cycle (longDRX cycle) and a DRX start offset (drxStartOffset), and the base station may optionally set a DRX short cycle timer (drxShortCycleTimer) and a short DRX cycle (shortDRX-Cycle). The long term DRX cycle provides a longer sleep period for the terminal than the short term DRX cycle. In addition, a HARQ round trip time (RTT) timer is defined for each downlink HARQ process.

The DRX start offset is a value that defines the subframe where the DRX cycle 400 begins. The DRX short cycle timer is a timer that defines the number of consecutive subframes for which the UE must follow a short DRX cycle. The HARQ RTT timer is a timer that defines the minimum number of subframes before the interval in which downlink HARQ retransmission is expected by the UE.

Referring back to FIG. 3, a method for the base station to reconfigure RRC-related parameters, particularly DRX-related parameters based on mobility indicators is as follows. For example, in the case of a fast terminal, a DRX cycle may be adjusted, changed, or reconfigured in consideration of a handover failure due to a radio link failure (RLF). For example, the base station may change the long term DRX cycle into smaller periods. Alternatively, the base station may change the long term DRX cycle into a short term DRX cycle. If only long-term DRX cycles are configured, short-term DRX cycles can also be configured simultaneously. While the long DRX cycle is running, the DRX configuration can be changed to increase the DRX inactivity interval. If the long-term DRX cycle before the change was sf = 160, then the change may consist of smaller cycles such as sf = 40 and the like.

As another example, the base station may configure or reconfigure the DRX related parameters to reduce battery consumption as much as possible according to the mobility indicator received from the terminal.

As another example, the base station may configure or reconfigure DRX related parameters so as to reduce traffic transmission delay to the maximum with reference to the mobility indicator.

As another example, the base station may configure or reconfigure the connection release timer, which is a timer for maintaining the connection of the terminal according to the mobility indicator. For example, in the case of a high speed terminal, the base station may configure the connection release timer to be relatively small so that the high speed terminal may quickly change from the RRC connected state to the RRC idle state. Alternatively, in the case of a low speed terminal, the base station may configure the connection release timer to be relatively large so that the low speed terminal may change to an RRC idle state after a longer time in the RRC connection state.

The base station transmits an RRC connection reconfiguration message including the reconfigured RRC related parameters to the terminal (S315). For example, when a DRX related parameter is included in the RRC connection reconfiguration message, the RRC connection reconfiguration message may include a syntax as shown in the following table.

DRX-Config :: = CHOICE {     release NULL,     setup SEQUENCE {         onDurationTimer ENUMERATED { psf1, psf2, psf3, psf4, psf5, psf6, psf8, psf10, psf20, psf30, psf40, psf50, psf60, psf80, psf100, psf200}, drx-InactivityTimer ENUMERATED { psf1, psf2, psf3, psf4, psf5, psf6, psf8, psf10, psf20, psf30, psf40, psf50, psf60, psf80, psf100, psf200, psf300, psf500, psf750, psf1280, psf1920, psf2560, psf0-v1020, spare9, spare8, spare7, spare6, spare5, spare4, spare3, spare2, spare1}, drx-RetransmissionTimer ENUMERATED { psf1, psf2, psf4, psf6, psf8, psf16, psf24, psf33}, longDRX-CycleStartOffset CHOICE { sf10 INTEGER (0..9), sf20 INTEGER (0..19), sf32 INTEGER (0..31), sf40 INTEGER (0..39), sf64 INTEGER (0..63), sf80 INTEGER (0..79), sf128 INTEGER (0..127), sf160 INTEGER (0..159), sf256 INTEGER (0..255), sf320 INTEGER (0..319), sf512 INTEGER (0..511), sf640 INTEGER (0..639), sf1024 INTEGER (0..1023), sf1280 INTEGER (0..1279), sf2048 INTEGER (0..2047), sf2560 INTEGER (0..2559) }, shortDRX SEQUENCE { shortDRX-Cycle ENUMERATED { sf2, sf5, sf8, sf10, sf16, sf20, sf32, sf40, sf64, sf80, sf128, sf160, sf256, sf320, sf512, sf640}, drxShortCycleTimer INTEGER (1..16)         } OPTIONAL-Need OR     } }

Referring to Table 1, DRX config is DRX configuration information including various DRX related parameters and may be included in a MAC-MainConfig message, which is an RRC message used to specify a main configuration of a MAC layer for a bearer. The DRX configuration information includes an onDurationTimer field defining a value of a duration timer, a drx-InactivityTimer field indicating a value of a DRX inactivity timer, and a drx-RetransmissionTimer field indicating a value of a DRX retransmission timer. In addition, the DRX configuration information includes a longDRX-CycleStartOffset field indicating a length of a long DRX cycle and a starting subframe, and a shortDRX field regarding a short DRX that may be configured as optional. The shortDRX field specifically includes a shortDRX-Cycle subfield that indicates the length of the short DRX cycle and a drxShortCycleTimer subfield that indicates the value of the short-term DRX cycle timer that the terminal consecutive.

The onDurationTimer field may be set to any one of {psf1, psf2, psf3, ... psf200}. psf means a PDCCH subframe, and the number after psf indicates the number of PDCCH subframes. That is, psf represents the expiration value of the timer as the number of PDCCH subframes. For example, if the onDurationTimer field = psf1, the duration timer expires after progressing cumulatively to one PDCCH subframe including the subframe where the DRX cycle started. Or the onDurationTimer field = psf4, the duration timer expires after progressing from the beginning of the DRX cycle cumulatively to the four PDCCH subframes. The drx-InactivityTimer field may be set to any one of {psf1, psf2, psf3, ... psf2560}. For example, if the drx-InactivityTimer field = psf3, the DRX inactivity timer expires after progressing up to three PDCCH subframes cumulatively, including the subframe at the time of driving. The drx-RetransmissionTimer field may be set to any one of {psf1, psf2, psf4, ... psf33}. For example, if the drx-RetransmissionTimer field = psf4, the DRX retransmission timer expires after progressing up to four PDCCH subframes including the subframe at the time when it is driven.

The longDRX-CycleStartOffset field may be set to any one of values of {sf10, sf20, sf32, sf40, ... sf2560} as the length of a long DRX cycle, and the subframe where the long DRX cycle starts is the length of the long DRX cycle. The value may be set to any one of {INTEGER (0..9), INTEGER (0..19), INTEGER (0..31), ... INTEGER (0..2559)}. For example, if the longDRX-CycleStartOffset field = sf20, INTEGER (0..19), one long DRX cycle includes 20 subframes, and the long DRX cycle includes any subframe of subframe indexes 0 to 19. This long term DRX cycle start subframe may be selected. The shortDRX-Cycle subfield constituting the shortDRX field may be set to any one of {sf2, sf5, sf8, ... sf640}. For example, if the shortDRX-Cycle subfield = sf5, one short DRX cycle includes 5 subframes. In addition, the drxShortCycleTimer subfield constituting the shortDRX field may indicate any one of integers 1 to 16. For example, if the drxShortCycleTimer subfield = 3, the short DRX cycle has gone through three times and then expires. The terminal configures the changed RRC related parameters in the terminal.

5 is a flowchart illustrating a method of supporting mobility of a terminal according to another example of the present invention.

Referring to FIG. 5, the base station transmits mobility support information (ueMobilityInfoAvail) to the terminal (S500). The mobility support information is information indicating whether or not the mobility indicator of the terminal can be received or used. This is because the base station may or may not perform radio resource configuration using the mobility indicator of the terminal according to its performance. From the point of view of the terminal, the base station may determine whether to check (or collect or transmit to the base station) the mobility indicator according to whether the mobility indicator of the terminal can be used. In other words, the terminal may use the mobility support information as a criterion for determining whether to use the mobility indicator of the terminal.

The mobility support information may indicate two things, either allowed or not allowed. When the mobility support information indicates 'allow', it means that the base station can receive or use the mobility indicator of the terminal. Alternatively, when the mobility support information indicates 'allow', this may mean that the base station allows the terminal to transmit the mobility indicator to the base station. In this case, the UE may know that the mobility indicator may be collected and transmitted to the base station. If the terminal not collecting the mobility indicator receives the mobility support information indicating 'allow', the terminal starts collecting the mobility indicator. On the other hand, when the mobility support information indicates 'not allowed', it means that the base station cannot receive or use the mobility indicator of the terminal. Alternatively, when the mobility support information indicates 'not allowed', this may mean that the base station does not allow the terminal to transmit the mobility indicator to the base station.

The mobility support information may be included in system information, for example. That is, the base station may transmit mobility support information through a broadcast control channel (BCCH) which is a logical channel. In general, since the base station may not be configured to use the mobility support information in the same manner, it is necessary for the base station to broadcast the mobility support information to a plurality of terminals. In order for the UE to perform an operation such as collecting the mobility indicator of the UE in the RRC idle state, the UE should receive system information about the base station in the RRC idle state. Therefore, the mobility support information is preferably transmitted to the terminal through the system information. The terminal may know whether the base station can receive the mobility indicator by receiving the mobility support information through the system information.

The base station may configure system information including mobility support information as follows.

-ASN1START SystemInformationBlockType1 :: = SEQUENCE { cellAccessRelatedInfo SEQUENCE { plmn-IdentityList PLMN-IdentityList, trackingAreaCode TrackingAreaCode, cellIdentity CellIdentity, cellBarred ENUMERATED {barred, notBarred}, intraFreqReselection ENUMERATED {allowed, notAllowed}, csg-Indication BOOLEAN, csg-Identity CSG-Identity OPTIONAL-Need OR }, ... systemInfoValueTag INTEGER (0..31), ueMobilityInfoAvail ENUMERATED {allowed, notAllowed} nonCriticalExtension SystemInformationBlockType1-v890-IEs OPTIONAL } -ASN1STOP

Referring to Table 2, the System Information Block Type 1 (SystemInformationBlockType1) includes mobility support information (ueMobilityInfoAvail). The mobility support information (ueMobilityInfoAvail) indicates allowed or notAllowed.

In addition to mobility support information, the base station may provide various information that the terminal may transmit, for example, assistant information for interference avoidance for in-device coexistence (IDC), and heterogeneous network (Hetnet). It should be able to inform the terminal whether the base station can receive the auxiliary information or the MBMS-related auxiliary information. That is, since the terminal can transmit various auxiliary information to the base station, the base station needs to clearly inform the terminal whether it is supported. Accordingly, the base station can be transmitted to the terminal in combination with other auxiliary information as auxiliary information on the mobility of the terminal. Ancillary information about the mobility of the terminal is a concept equivalent to the mobility support information. The following table is an example of a system information syntax including information on support of auxiliary information transmitted by a base station.

-ASN1START SystemInformationBlockType14 :: = SEQUENCE { idcFreqInfo ENUMERATED {allowed, notAllowed} hetNetInfo ENUMERATED {allowed, notAllowed} ueMobilityInfoAvail ENUMERATED {allowed, notAllowed} lateNonCriticalExtension OCTET STRING OPTIONAL-Need OP } -ASN1STOP

Referring to Table 3, whether the auxiliary information is supported is included in the system information block type 14. Here, the idcFreqInfo field indicates whether the base station supports IDC related auxiliary information. The hetNetInfo field indicates whether the base station supports HetNet related auxiliary information. The ueMobilityInfoAvail field indicates whether or not assistance information regarding mobility of the terminal is supported. If the value of each information field is 'allowed', this indicates that the base station supports the corresponding auxiliary information. If not, it indicates that the base station does not support the auxiliary information.

On the other hand, the information about the support of the auxiliary information in the system information may be configured in the form of a bitmap (bitmap) or bit string (bit string) as shown in the table below.

-ASN1START SystemInformationBlockType14 :: = SEQUENCE { ueAssistantInfo BIT STRING (SIZE (X)), lateNonCriticalExtension OCTET STRING OPTIONAL-Need OP } -ASN1STOP

Referring to Table 4, the ueAssistantInfo field may indicate whether a variety of auxiliary information is supported in a bit string format. In SIZE (X), X is a bit length of the ueAssistantInfo field and may be equal to the number of auxiliary information supported by the base station. For example, if a base station capable of supporting three auxiliary information such as idcFreqInfo, hetNetInfo, and ueMobilityInfoAvail, X = 3, and the number of bits of the ueAssistantInfo field is three. Each bit sequentially corresponds to the respective auxiliary information. If the bit of the ueAssistantInfo field is abc, bit a corresponds to idcFreqInfo, bit b corresponds to hetNetInfo, and bit c corresponds to ueMobilityInfoAvail. A value of 0 indicates that auxiliary information corresponding to the bit is not supported by the base station, and a value of 1 indicates that the corresponding auxiliary information is supported by the base station. For example, if the ueAssistantInfo field is equal to 001, the base station does not support idcFreqInfo, hetNetInfo, and ueMobilityInfoAvail.

Upon receiving the system information including the mobility support information or the assistance information from the base station, the terminal checks the indication of the mobility support information or the assistance information. If the mobility support information indicates 'not allowed', the terminal does not check the mobility of the terminal and does not collect the mobility index. On the other hand, if the mobility support information indicates 'not allowed', the terminal checks the mobility of the terminal. That is, the terminal may adaptively check the mobility of the terminal according to the content of the mobility support information (S505). The terminal generates a mobility indicator corresponding to the mobility of the checked terminal (S510) and transmits the generated mobility indicator to the base station (S515), and the base station transmits an RRC connection reconfiguration message including the reconfigured RRC related parameters to the terminal. (S520). Generation and transmission of the mobility indicator and transmission of the RRC connection reconfiguration message may be performed in the same manner as the operations of steps S305, S310, and S315, respectively.

6 is a flowchart illustrating a method of supporting mobility of a terminal according to another embodiment of the present invention.

Referring to FIG. 6, the base station transmits UE mobility inquiry information to the terminal (S600). The mobility query information of the terminal is information that the base station inquires of the terminal whether the terminal can transmit (or collect or check) the mobility indicator. In this case, the base station may query the entire information regarding the overall performance of the terminal as well as the query whether the terminal supports the transmission of the mobility indicator. The terminal transmits the mobility capability information of the terminal to the base station according to the mobility query information of the terminal received from the base station (S605). In order to exchange the mobility query information and the mobility capability information of the terminal, the terminal and the base station may use a UE capability enquiry procedure. In this case, in step S600, the mobility query information of the terminal may be included in a terminal capability inquiry message (UECapabilityEnquiry Message) and transmitted. In operation S605, the mobility capability information of the UE may be included in the UE capability information (UEcapabilityInformation) and transmitted. In more detail, the terminal performance information may be configured with a syntax such as the following table.

-ASN1START UE-EUTRA-Capability :: = SEQUENCE { accessStratumRelease AccessStratumRelease, ue-Category INTEGER (1..5), pdcp-Parameters PDCP-Parameters, phyLayerParameters PhyLayerParameters, rf-Parameters RF-Parameters, measParameters MeasParameters, featureGroupIndicators BIT STRING (SIZE (32)) OPTIONAL, interRAT-Parameters SEQUENCE { utraFDD IRAT-ParametersUTRA-FDD OPTIONAL, utraTDD128 IRAT-ParametersUTRA-TDD128 OPTIONAL, utraTDD384 IRAT-ParametersUTRA-TDD384 OPTIONAL, utraTDD768 IRAT-ParametersUTRA-TDD768 OPTIONAL, geran IRAT-ParametersGERAN OPTIONAL, cdma2000-HRPD IRAT-Parameters CDMA2000-HRPD OPTIONAL, cdma2000-1xRTT IRAT-ParametersCDMA2000-1XRTT OPTIONAL }, nonCriticalExtension UE-EUTRA-Capability-v920-IEs OPTIONAL } UE-EUTRA-Capability-new-IEs :: = SEQUENCE { ueAssistantInfo BIT STRING (SIZE (X)), nonCriticalExtension SEQUENCE {} OPTIONAL } -ASN1STOP

Referring to Table 5, the UE-EUTRA-Capability field is UE capability information, and includes detailed capability information in IE UE-EUTRA-Capability in a container of a UE-CapabilityRAT-ContainerList. Meanwhile, the UE-EUTRA-Capability-new-IEs field is new terminal capability information and includes an auxiliary information (ueAssistantInfo) field of the terminal. The auxiliary information field of the terminal indicates whether or not it supports at least one of auxiliary information for coexistence interference avoidance (IDC) in the device, assistance information related to heterogeneous networks, assistance information related to MBMS, and assistance information regarding mobility of the terminal. The auxiliary information field of the terminal may have a form of a bit string or a bitmap and may have a length X corresponding to the number of auxiliary information supported by the terminal.

For example, if a terminal capable of supporting three pieces of auxiliary information such as idcFreqInfo, hetNetInfo, and ueMobilityInfoAvail, X = 3, and the number of bits of the ueAssistantInfo field is three. Each bit sequentially corresponds to the respective auxiliary information. If the bit of the ueAssistantInfo field is abc, bit a corresponds to idcFreqInfo, bit b corresponds to hetNetInfo, and bit c corresponds to ueMobilityInfoAvail. If the value of the bit is 0, it indicates that the corresponding auxiliary information is not supported by the terminal. If the value of the bit is 1, it indicates that the corresponding auxiliary information is supported by the terminal. For example, if the ueAssistantInfo field is equal to 001, the terminal does not support idcFreqInfo, hetNetInfo, and ueMobilityInfoAvail.

Or, although not shown in Table 5, the new UE capability information (UE-EUTRA-Capability-new-IEs) may include only mobility capability information (ueMobilityInfoAvail) of the terminal, not other auxiliary information. In this case, the mobility performance information of the terminal indicates whether the terminal can collect the mobility indicator or support signaling about the mobility indicator.

Based on the mobility performance information of the terminal, the base station can distinguish which terminal supports mobility performance and which terminal does not support mobility performance. The base station determines the need for the mobility indicator for the terminal supporting the mobility performance, and then transmits the mobility support information (mobility support information or ueMobilityInfoAvail) to the terminal (S610). As a result, the base station can inform the terminal whether it can receive the mobility indicator of the terminal. Alternatively, the base station may allow (or allow, command) the terminal to transmit the mobility indicator to the base station. Alternatively, the base station may inform the terminal that the mobile station supports the transmission of the mobility indicator only for the specific terminal. As such, since the mobility support information is specifically transmitted to the terminal, the mobility support information may be transmitted through a dedicated control channel (DCCH), which is a logical channel. For example, mobility support information may be transmitted through an RRC connection setup message. This can prevent the problem that the base station unnecessarily receives the mobility indicator by all the terminals always transmit the mobility indicator. Furthermore, the signaling congestion of the network can be reduced by allowing the terminal to transmit the mobility indicator to the base station only through the terminal permitted through the mobility support information.

When the base station permits the transmission of the mobility indicator to the terminal according to the content of the mobility support information, or confirms that the base station can receive the mobility indicator, the terminal may adaptively check the mobility of the terminal (S615). The terminal generates a mobility indicator corresponding to the mobility of the checked terminal (S620) and transmits the generated mobility indicator to the base station (S625), and the base station transmits an RRC connection reconfiguration message including the reconfigured RRC related parameters to the terminal. (S630). Generation and transmission of the mobility indicator and transmission of the RRC connection reconfiguration message may be performed in the same manner as the operations of steps S305, S310, and S315, respectively.

On the other hand, in step S610, the base station may transmit to the terminal dedicated or not (dedicatedly) whether to support the other assistance in addition to the mobility support information of the terminal. Because the base station can receive not only mobility support information, but also various information that can be transmitted by the terminal, for example, auxiliary information for coexistence interference avoidance (IDC) in a device, assistance information for heterogeneous networks, or assistance information related to MBMS. This is because it should be able to inform the terminal if it can. That is, since the terminal can transmit various auxiliary information to the base station, the base station needs to clearly inform the terminal whether it is supported. Ancillary information about the mobility of the terminal is a concept equivalent to the mobility support information. The table below is an example of a syntax including auxiliary information transmitted by a base station.

{ idcFreqInfo ENUMERATED {allowed, notAllowed} hetNetInfo ENUMERATED {allowed, notAllowed} ueMobilityInfoAvail ENUMERATED {allowed, notAllowed} }

Referring to Table 6, the idcFreqInfo field indicates whether the base station supports IDC related auxiliary information. The hetNetInfo field indicates whether the base station supports HetNet related auxiliary information. The ueMobilityInfoAvail field indicates whether or not assistance information regarding mobility of the terminal is supported. If the value of each information field is 'allowed', this indicates that the base station supports the corresponding auxiliary information. If not, it indicates that the base station does not support the auxiliary information.

Meanwhile, whether the mobility support information and other auxiliary information are supported may be configured in the form of a bitmap or a bit string in the system information SystemInformationBlockType14 as shown in the following table.

-ASN1START SystemInformationBlockType14 :: = SEQUENCE { ueAssistantInfo BIT STRING (SIZE (X)), lateNonCriticalExtension OCTET STRING OPTIONAL-Need OP } -ASN1STOP

Referring to Table 7, the ueAssistantInfo field may indicate whether a variety of auxiliary information is supported in a bit string format. In SIZE (X), X is a bit length of the ueAssistantInfo field and may be equal to the number of auxiliary information supported by the base station. For example, if a base station capable of supporting three auxiliary information such as idcFreqInfo, hetNetInfo, and ueMobilityInfoAvail, X = 3, and the number of bits of the ueAssistantInfo field is three. Each bit sequentially corresponds to the respective auxiliary information.

On the other hand, in step S610, the mobility support information of the terminal may have a function of instructing the terminal to stop the transmission of the current mobility indicator. For example, the base station defines the mobility support information as a flag of 1 bit, and if the flag is set to 1, the base station indicates that the base station can receive the mobility indicator or indicates that the terminal requires the mobility indicator to be transmitted. can do. On the other hand, if the flag is set to 0, it may indicate that the base station is unable to receive the mobility indicator or may indicate that the terminal stops transmitting the mobility indicator.

On the other hand, when the steps S600 and S605 are performed based on the terminal performance query procedure may be independent of the steps below the step S610. That is, steps S600 and S605 may be separate procedures from steps below S610. In other words, S610, S615, S620, S625, and S630 may not proceed immediately after steps S600 and S605. For example, the base station can check only the performance information of the terminal in step S600, S605 and the like. Thereafter, the base station may transmit a message of a step such as S610, S615, S620, S625, S630 at a desired time.

7 is a flowchart illustrating a method of supporting mobility of a terminal according to another embodiment of the present invention.

Referring to FIG. 7, the terminal in the RRC idle state transmits an RRC connection request message to the base station (S700). The RRC connection request message is a message that the terminal first transmits to the base station for RRC connection establishment. The RRC connection request message may include information indicating that the terminal can support the mobility indicator. That is, the terminal may transmit an RRC connection request message including information indicating that the mobility indicator can be supported to the base station.

The base station transmits an RRC connection setup message including mobility support information to the terminal (S705). Although not shown in the drawing, when the terminal transmits terminal performance information indicating that the terminal supports the capability of transmitting or collecting the mobility indicator to the base station, the base station transmits or collects the mobility indicator by using the terminal capability information. You can see that it supports. The base station transmits to the terminal by including the mobility support information in the RRC connection configuration message that allows the terminal to transmit the mobility indicator. In one embodiment, the RRC connection establishment message may indicate, in the form of 'allowed' or 'notAllowed', whether the base station supports not only mobility assistance information, but also other assistance information (eg, IDC related assistance information, HetNet related assistance information, etc.). It may be.

The terminal transmits an RRC connection setup complete message including a mobility indicator to the base station (S710). The base station may receive the mobility indicator included in the RRC connection establishment complete message, and may change or reconfigure RRC related parameters, such as DRX related parameters, based on the received mobility indicator.

The base station transmits an RRC connection reconfiguration message including the changed RRC related parameters to the terminal (S715). For example, when the changed RRC related parameter is a DRX related parameter, the base station transmits DRX configuration information (DRX config) shown in Table 1 including the changed DRX related parameter to the terminal through an RRC connection reconfiguration message.

As another embodiment, the terminal in the RRC dormant state in S700 may transmit an RRC connection request message including the mobility indicator to the base station, not information indicating that the terminal can support the mobility indicator. The base station may receive the mobility indicator included in the RRC connection request, and change or reconfigure RRC related parameters, such as DRX related parameters, based on the received mobility indicator.

Here, the fact that the terminal transmits the mobility indicator may mean that the base station has already allowed the transmission of the mobility indicator (that is, the base station has already transmitted the mobility support information). In this case, the mobility support information may be transmitted by the base station to the terminal through the broadcast control channel (BCCH) in step S500. Alternatively, the UE may transmit the mobility indicator to the base station without the step of allowing the UE to transmit the mobility indicator in the broadcast control channel (BCCH). In this case, the terminal may configure the mobility indicator by using a 1-bit indicator corresponding to a flag such as high speed (H) or low speed (L). Similarly, the UE may include the mobility indicator in the RRC connection establishment complete message of step S710 without transmitting the mobility indicator by the RRC connection establishment message.

In the above description, the mobility indicator was handled separately from the auxiliary information, and the mobility indicator and the auxiliary information were described as being transmitted through different routes as different information. However, the mobility indicator may be transmitted along with the supplementary information. That is, the mobility indicator may be transmitted in parallel with other auxiliary information as one auxiliary information. A method of transmitting the mobility indicator as auxiliary information is described below.

8 is a flowchart illustrating a method of supporting mobility of a terminal according to another embodiment of the present invention.

Referring to FIG. 8, steps S800 to S810 are performed by the same procedure as steps S700 to S710, respectively. In step S815, the terminal transmits an RRC UE assistant information message to the base station. The RRC terminal assistance information message is an RRC message that the terminal provides the base station with assistance information supported by the terminal, including the mobility indicator. It is also referred to as terminal assistance information by shortening assistance information supported by the terminal. The terminal assistance information may be transmitted through a dedicated control channel (DCCH), which is a logical channel separately provided for transmitting the terminal assistance information. Such a dedicated RRC message may be referred to as an RRC terminal assistance information message.

The RRC terminal assistance information message may include terminal assistance information, for example, assistant information for interference avoidance for in-device coexistence (IDC), assistance information related to a heterogeneous network, and MBMS. Includes information used to improve system performance, such as supplementary information and supplemental information for various enhancements of Diverse Data Application (eDDA). Here, the auxiliary information for the eDDA may include a mobility index. Alternatively, the mobility indicator may be terminal assistance information separate from the eDDA. In any case, the mobility indicator is treated as terminal assistance information.

The terminal assistance information is transmitted by the RRC terminal assistance information message which is a dedicated RRC message separate from the RRC connection request message or the RRC connection setup complete message. A signaling radio bearer (SRB1) is used for transmission of the RRC terminal assistance message, and a communication mode in radio link control (RLC) is an acknowledgment mode (AM). Meanwhile, a dedicated control channel (DCCH) is used as a logical channel for transmitting the RRC terminal assistance message, and is transmitted from the terminal to the wireless telecommunication network.

The RRC terminal assistance message may be configured with a syntax of the form shown in the following table.

-ASN1START RRCAssistInfoTrans :: = SEQUENCE { rrc-TransactionIdentifier RRC-TransactionIdentifier, criticalExtensions CHOICE { c1 CHOICE { rrcAssistInfoTrnas -r11 RRCAssistInfoTrnas -r11-IEs, spare3 NULL, spare2 NULL, spare1 NULL }, criticalExtensionsFuture SEQUENCE {} } } RRCAssistInfoTrans-new-IEs :: = SEQUENCE { mbmsAssistInfo MBMSInfo OPTIONAL, idcAssistInfo IDCInfo OPTIONAL, hetNetAssistInfo HetNetInfo OPTIONAL, eddaAssistInfo eDDAInfo OPTIONAL, nonCriticalExtension SEQUENCE {} OPTIONAL } MBMSInfo :: = SEQUENCE { mbmsFrequenyList SEQUENCE (SIZE (1..MaxMBMSFreq)) OF MBMSFrequencyInfo, mbmsPreferInfo ENUMERATED {MBMS, nonMBMS}, } MaxMBMSFreq INTEGER :: = Maximum MBMSFrequency Possible MBMSFrequencyInfo :: SEQUENCE { frequencyInfo ARFCN-ValueEUTRA, mbmsSvcInfo TMGI } IDCInfo :: = SEQUENCE { idcUnusableFreqList SEQUENCE (SIZE (1..MaxFreq)) OF IDCUnusableFreqInfo, idctdmPattern IDCTDMPatternInfo, idcInfo IDCInfo (other idc information) } IDCUnusableFreqInfo :: SEQUENCE { frequencyInfo ARFCN-ValueEUTRA, } eDDAInfo :: = SEQUENCE { uePreferInfo ENUMERATED {powSave, nonPowSave} OPTIONAL, ueMobilityInfo ENUMERATED {high, medium, normal, Low} OPTIONAL, eDDAInfo EDDAInfo (Other eDDA information) } HetNetInfo :: = SEQUENCE { hetNetInfo HetNetInfo (Other hetnet information) }

Referring to Table 8, the RRC terminal assistance information (RRCAssistantInfoTrans) message may include an RRCAssistInfoTrans part including existing terminal assistance information and an RRCAssistInfoTrans-new part including terminal assistance information according to an embodiment of the present invention. have. The RRCAssistInfoTrans part contains the rrc-TransactionIdentifier field. The RRCAssistInfoTrans-new part includes MBMS-related assistance information (mbmsAssistInfo), assistance information for interference avoidance for in-device coexistence (IDC) (IDCInfo), assistance information regarding heterogeneous networks (HetNetInfo), various Includes supplemental information (eDDAInfo) for enhancements of Diverse Data Application (eDDA). Here, the MBMS-related auxiliary information includes an MBMS Info (MBMSInfo) field to be transmitted by the UE, and the MBMS Info (MBMSInfo) field includes an MBMSFrequencyInfo field which is a list of frequencies for which the UE receives the MBMS service, and an mbmsSvcInfo field indicating the type of the MBMS service. And an mbmsPreferInfo field indicating the service priority of the terminal. Here, the MBMS priority may preferentially support the MBMS service. If it is not the MBMS priority, the MBMS service may not be preferentially supported.

The auxiliary information (IDCInfo) for avoiding coexistence interference in the device includes a frequencyInfo field which is a list of frequencies in which an IDC problem may occur.

The supplementary information (eDDAInfo) for strengthening various data applications may include an uePreferInfo field which is information on a preference of a terminal and / or an ueMobilityInfo field which is a mobility index of the terminal. Here, when the value of the uePreferInfo field indicates powSave, it indicates that the terminal is a mode that supports minimization of battery consumption. On the other hand, when the value of the uePreferInfo field indicates nonPowSave, it indicates that the terminal does not support the minimization of battery consumption.

Meanwhile, the ueMobilityInfo field, which is a mobility indicator, may not be included in auxiliary information (eDDAInfo) for enhancing various data applications and may be defined as individual information. That is, each terminal assistance information is not always included in the RRC terminal assistance information message all at the same time, the terminal may include only the terminal assistance information requested by the base station in the RRC terminal assistance information message. Accordingly, the MBMSInfo field, the IDCInfo field, the HetNetInfo field, and the eDDAInfo fields may be separately generated and transmitted to the base station. This is because the nature of each terminal assistance information and the generation time or reporting time may be different. For example, mobility related information such as a uePreferInfo field and a ueMobilityInfo field may be reported to a base station separately regardless of other terminal assistance information.

The RRC terminal assistance message may be configured with a syntax of a format as shown in the following table.

-ASN1START RRCAssistInfoTrans :: = SEQUENCE { uePreferInfo ENUMERATED {powSave, nonPowSave} OPTIONAL, ueMobilityInfo ENUMERATED {high, medium, normal, Low} OPTIONAL, mbmsFrequenyList SEQUENCE (SIZE (1..MaxMBMSFreq)) OF MBMSFrequencyInfo, OPTIONAL mbmsPreferInfo ENUMERATED {MBMS, nonMBMS}, OPTIONAL idcUnusableFreqList SEQUENCE (SIZE (1..MaxFreq)) OF IDCUnusableFreqInfo, OPTIONAL idctdmPattern IDCTDMPatternInfo, OPTIOANL hetNetInfo HetNetInfo, OPTIONAL Other UE Assistant Information }

Referring to Table 9, the ueMobilityInfo field is included in the RRC terminal assistance message as information corresponding to other terminal assistance information, for example, the uePreferInfo field, the mbmsFrequencyList field, the mbmsPreferInfo field, the idcUnusableFreqList field, the idctdmPattern field, and the HetNetInfo field. Each field may be included in the RRC UE assistance message as OPTIONAL.

Meanwhile, the dedicated RRC message used for transmitting the terminal assistance information including the mobility indicator may be an RRC connection request message or an RRC connection setup complete message, not an RRC terminal assistance information message. In other words, when the terminal assistance information is included in the RRC connection request message or the RRC connection establishment complete message, it may be determined that the RRC connection request message is used instead of the RRC terminal assistance information message. For example, in step S710, the terminal may transmit the terminal assistance information in the RRC connection setup complete message. Alternatively, in the case of step S700, the terminal may be transmitted by including the terminal assistance information in the RRC connection request message.

In addition, in steps S310, S515, and S625 of the terminal transmitting the mobility indicator, the terminal may transmit the terminal assistance information together with the mobility indicator to the base station.

Meanwhile, in FIG. 8, it is described that the terminal performs the step of transmitting the RRC terminal assistance message (S815) after the step of transmitting the RRC connection setup complete message (S810). However, a step (S812 (not shown in the figure)) of the base station transmitting an RRC connection reconfiguration message to the terminal may be further performed between steps S810 and S815. In this case, the terminal may perform S815 at a necessary time after S812 is performed.

9 is an operation flowchart of a terminal supporting mobility of the terminal according to an embodiment of the present invention.

Referring to FIG. 9, the terminal receives UE mobility enquiry information from the base station. The mobility query information of the terminal is information that the base station inquires of the terminal whether the terminal can transmit (or collect or check) the mobility indicator. In this case, the base station may query the entire information regarding the overall performance of the terminal as well as the query whether the terminal supports the transmission of the mobility indicator. The terminal transmits mobility capability information of the terminal to the base station according to the mobility query information received from the base station. In order to exchange the mobility query information and the mobility capability information of the terminal, the terminal and the base station may use a UE capability enquiry procedure. In this case, the mobility query information of the terminal may be included in the UE capability inquiry message and transmitted. The mobility capability information of the terminal may be included in the UE capability information (UEcapabilityInformation) and transmitted. In more detail, the terminal performance information may be configured with a syntax such as Table 5 above.

The terminal receives mobility support information (ueMobilityInfoAvail) from the base station. The mobility support information is information indicating whether or not the mobility indicator of the terminal can be received or used. This is because the base station may or may not perform radio resource configuration using the mobility indicator of the terminal according to its performance. From the point of view of the terminal, the base station may determine whether to check (or collect or transmit to the base station) the mobility indicator according to whether the mobility indicator of the terminal can be used. In other words, the terminal may use the mobility support information as a criterion for determining whether to use the mobility indicator of the terminal. Specific functions and contents of the mobility support information are the same as the description of step S500.

On the other hand, the terminal may be dedicated (dedicatedly) receiving the support information as well as the mobility support information. Because the base station can receive not only mobility support information, but also various information that can be transmitted by the terminal, for example, auxiliary information for coexistence interference avoidance (IDC) in a device, assistance information for heterogeneous networks, or assistance information related to MBMS. This is because it should be able to inform the terminal if it can. That is, since the terminal can transmit various auxiliary information to the base station, the base station needs to clearly inform the terminal whether it is supported.

The terminal checks the mobility of the terminal (S900). As an example, the terminal may check the mobility of the terminal based on the number of cell selections. As another example, the terminal may check the mobility of the terminal based on the actual measurement speed.

The terminal generates a mobility indicator corresponding to the mobility of the checked terminal (S905). The terminal may express the mobility indicator in various forms. As an example, the terminal may indicate the number of cell selections of the terminal itself as a mobility indicator. For example, if the number of cell selections of the terminal is 5 for a unit time, the terminal displays as follows: mobility indicator = 5. The mobility indicator is then indicated in the form of an integer.

As another example, the terminal may indicate the speed itself at which the terminal moves as a mobility indicator. For example, if the speed of the terminal directly measured by the terminal is 35 km / h, the terminal may display the mobility indicator = 35 km / h.

As another example, the terminal may indicate a level of the moving speed as a mobility indicator, such as 'mobility indicator = high speed' or 'mobility indicator = low speed'.

The terminal transmits a mobility indicator to the base station (S910). The mobility indicator may be transmitted not only by higher layer signaling such as an RRC message but also by lower layer signaling such as a MAC layer or a physical layer.

The terminal receives an RRC connection reconfiguration message from the base station (S915). The RRC connection reconfiguration message includes RRC related parameters, in particular DRX related parameters, reconfigured by the base station based on the mobility indicator. If DRX-related parameters are included in the RRC connection reconfiguration message, the RRC connection reconfiguration message may include the syntax shown in Table 1 above.

10 is a flowchart illustrating an operation of a base station supporting mobility of a terminal according to an embodiment of the present invention.

Referring to FIG. 10, the base station transmits UE mobility enquiry information to the terminal. The mobility query information is information that the base station inquires of the terminal whether the terminal can transmit (or collect or check) the mobility indicator. In this case, the base station may query the entire information regarding the overall performance of the terminal as well as the query whether the terminal supports the transmission of the mobility indicator.

The base station receives the mobility capability information of the terminal from the terminal. In order to exchange the mobility query information and the mobility capability information of the terminal, the terminal and the base station may use a UE capability enquiry procedure. In this case, the mobility query information of the terminal may be included in the UE capability inquiry message and transmitted. The mobility capability information of the terminal may be included in the UE capability information (UEcapabilityInformation) and received. In more detail, the terminal performance information may be configured with a syntax such as Table 5 above.

The base station transmits mobility support information (uebility support information or ueMobilityInfoAvail) to the terminal. The mobility support information is information indicating whether or not the mobility indicator of the terminal can be received or used. This is because the base station may or may not perform radio resource configuration using the mobility indicator of the terminal according to its performance. From the point of view of the terminal, the base station may determine whether to check (or collect or transmit to the base station) the mobility indicator according to whether the mobility indicator of the terminal can be used. In other words, the terminal may use the mobility support information as a criterion for determining whether to use the mobility indicator of the terminal. Specific functions and contents of the mobility support information are the same as the description of step S500.

On the other hand, the base station may be dedicated to transmit the mobility support information and whether the other auxiliary information is supported (dedicatedly) to the terminal. Because the base station can receive not only mobility support information, but also various information that can be transmitted by the terminal, for example, auxiliary information for coexistence interference avoidance (IDC) in a device, assistance information for heterogeneous networks, or assistance information related to MBMS. This is because it should be able to inform the terminal if it can. That is, since the terminal can transmit various auxiliary information to the base station, the base station needs to clearly inform the terminal whether it is supported.

The base station receives the mobility indicator from the terminal (S1000). The mobility indicator may be transmitted not only by higher layer signaling such as an RRC message but also by lower layer signaling such as a MAC layer or a physical layer.

The base station reconfigures the RRC related parameters, particularly the DRX related parameters, based on the mobility indicator (S1005). For example, in the case of a fast terminal, a DRX cycle may be adjusted, changed, or reconfigured in consideration of a handover failure due to a radio link failure (RLF). For example, the base station may change the long term DRX cycle into smaller periods. Alternatively, the base station may change the long term DRX cycle into a short term DRX cycle. If only long-term DRX cycles are configured, short-term DRX cycles can also be configured simultaneously. While the long DRX cycle is running, the DRX configuration can be changed to increase the DRX inactivity interval. If the long term DRX cycle before the change was sf = 160, then the change may consist of shorter cycles such as sf = 40 and the like.

As another example, the base station may configure or reconfigure the DRX related parameters to reduce battery consumption as much as possible according to the mobility indicator received from the terminal.

As another example, the base station may configure or reconfigure DRX related parameters so as to reduce traffic transmission delay to the maximum with reference to the mobility indicator.

As another example, the base station may configure or reconfigure the connection release timer, which is a timer for maintaining the connection of the terminal according to the mobility indicator. For example, in the case of a high speed terminal, the base station may configure the connection release timer to be relatively small so that the high speed terminal may quickly change from the RRC connected state to the RRC idle state. Alternatively, in the case of a low speed terminal, the base station may configure the connection release timer to be relatively large so that the low speed terminal may change to an RRC idle state after a longer time in the RRC connection state.

The base station transmits an RRC connection reconfiguration message including the reconfigured RRC related parameters to the terminal (S1010). For example, when the DRX related parameter is included in the RRC connection reconfiguration message, the RRC connection reconfiguration message may include a syntax as shown in Table 1 above.

11 is a block diagram illustrating a terminal and a base station supporting mobility of the terminal according to an embodiment of the present invention.

Referring to FIG. 11, the terminal 1100 includes a receiver 1105, a terminal processor 1110 and a transmitter 1115. The terminal processor 1110 further includes a message processor 1111 and a mobility checker 1112.

The receiver 1105 receives the mobility support information, the RRC connection reconfiguration message, the RRC connection configuration message, the mobility query information, and the like from the base station 1150. The receiver 1105 then sends the received information or messages to the message processor 1111.

The message processor 1111 analyzes or interprets the syntax of information or messages received from the receiver 1105. In particular, the message processor 1111 may analyze or interpret a message or information in a format as shown in Tables 1 to 7. For example, the message processor 1111 parses the mobility support information to determine whether the base station 1150 supports the mobility of the terminal 1100 or can receive the mobility indicator or transmits the mobility indicator by the terminal. You can check whether it allows. Alternatively, the message processor 1111 analyzes the syntax of the RRC connection reconfiguration message and configures the changed (or reconfigured) RRC related parameters included in the RRC connection reconfiguration message in the terminal 1100.

In addition, the message processor 1111 informs each layer of the terminal 1100 of the terminal 1100 to perform an indication of each information or message. Here, the layer may include an RRC layer and a MAC layer. Each layer that is instructed by the message processor 1111 may perform a function according to the corresponding instruction. For example, in view of the mobility support information, when the base station 1150 can support the mobility of the terminal 1100, the message processor 1111 notifies the mobility checker 1112 to the mobility checker 1112. The mobility of the terminal 1100 is checked.

The mobility checker 1112 checks the mobility of the terminal 1100. The mobility checker 1112 may check the mobility of the terminal 1100, for example, for a predetermined time or unit time or periodically or for a time designated by the message processor 1111.

The mobility checker 1112 increases the number of cell selections by 1 each time the terminal 1100 selects an initial cell as in step S220 or reselects a cell as in step S250, and accumulates the number of cell selections accumulated during a unit time. Determine the mobility indicator according to. If the number of cell selections accumulated during the unit time is relatively large, it is estimated that the terminal 1100 is moving at a high speed. Thus, the mobility checker 1112 determines the mobility index as 'high speed'. On the other hand, if the number of cell selections accumulated during the unit time is relatively small, it is assumed that the terminal 1100 is moving at a low speed. Thus, the mobility checker 1112 determines the mobility index as 'low speed'.

More specifically, the mobility checker 1112 includes the terminal 1100 checking whether the number of cell selections reaches a predefined threshold number of times within a unit time. When the number of cell selections is checked to reach a predefined threshold number of times within a unit time, the mobility of the terminal 1100 is estimated to correspond to high speed. Thus, the mobility checker 1112 determines the mobility index as 'high speed'. On the other hand, if the number of cell selections does not reach a predefined threshold number within a unit time, the mobility of the terminal 1100 is estimated to correspond to a low speed. Thus, the mobility checker 1112 determines the mobility index as 'low speed'. In other words, the terminal 1100 is classified as a high speed terminal when the cell selection is counted more than a predetermined number of times within a unit time, and a low speed terminal when the cell selection is counted less than a predetermined number of times. Can be classified as Alternatively, if the cell selection has an intermediate number of times within a unit time, it may be classified as a middle speed terminal.

As another example, the mobility checker 1112 may check the mobility of the terminal 1100 based on the actual measurement speed.

The mobility checker 1112 transmits the mobility of the checked terminal 1100 to the message processor 1111, and the message processor 1111 generates a mobility index corresponding to the mobility of the checked terminal. The message processor 1111 may express the mobility indicator in various forms. As an example, the message processor 1111 may indicate the number of cell selections of the terminal 1100 as a mobility indicator. For example, if the number of cell selections of the terminal 1100 is 5 for a unit time, the message processor 1111 displays as follows: mobility indicator = 5. The mobility indicator is then indicated in the form of an integer.

As another example, the message processor 1111 may represent the speed itself at which the terminal 1100 moves as a mobility indicator. For example, if the speed of the terminal 1100 directly measured by the mobility checker 1112 is 35 km / h, the message processor 1111 may display “mobility index = 35 km / h”.

As another example, the message processor 1111 may represent a level of the moving speed as the mobility indicator, such as 'mobility indicator = high speed' or 'mobility indicator = low speed'. For example, in the case of defining only two types of speed levels, high speed and low speed, the message processing unit 1111 defines the mobility indicator as 1 bit information, but the mobility indicator is 1 for high speed, and the mobility indicator is 0 for low speed. Can be directed. In the case of indicating other additional information such as medium speed, the mobility indicator may be defined as 2-bit information. For example, if the mobility index is 00, the movement speed is 0; if the mobility index is 01, the movement speed is high; if the mobility indicator is 10, the movement speed is medium speed; if the mobility indicator is 11, the movement speed is low. Can be. The representation form may be variably defined.

The message processor 1111 may generate the mobility indicator by using any one of various methods of representing the mobility indicator as described above.

When the message processor 1111 sends the generated mobility indicator to the transmitter 1115, the transmitter 1115 transmits the mobility indicator to the base station 1150. In this case, the message processor 1111 may generate and transmit terminal assistance information including the mobility indicator to the transmitter 1115. In this case, the transmitter 1115 transmits the generated terminal assistance information to the base station 1150. .

Meanwhile, the message processor 1111 may generate an RRC UE assistant information message including UE assistance information. For example, the RRC terminal assistance message may be composed of the syntax of Table 8 or Table 9. The terminal assistance information may be transmitted through a dedicated control channel (DCCH), which is a logical channel separately provided for transmitting the terminal assistance information. The dedicated RRC message may be referred to as an RRC terminal assistance information message. Terminal assistance information may include assistant information for interference avoidance for in-device coexistence (IDC), assistance information related to heterogeneous networks, or assistance information related to MBMS, and various data application enhancements (eDDA). It may include at least one of the auxiliary information for. Here, the mobility indicator may be included in the supplementary information for the eDDA or may be supplementary information separate from the supplementary information for the eDDA. The terminal assistance information is transmitted by the RRC terminal assistance information message which is a dedicated RRC message separate from the RRC connection request message or the RRC connection setup complete message.

Meanwhile, the message processing unit 1111 may include the terminal assistance information in the RRC connection request message or the RRC connection setup complete message instead of the RRC terminal assistance information message.

The transmitter 1115 transmits a mobility indicator, an RRC connection request message, an RRC connection setup complete message, mobility performance information, an RRC terminal assistance information message, and the like to the base station 1150.

The base station 1150 includes a transmitter 1155, a base station processor 1160, and a receiver 1165. The base station processor 1160 includes a message processor 1162 and a parameter changer 1161.

The transmitter 1155 transmits mobility support information, an RRC connection reconfiguration message, an RRC connection configuration message, and a mobility query information to the terminal 1100.

The receiver 1165 receives a mobility indicator, an RRC connection request message, an RRC connection setup complete message, mobility performance information, and the like from the terminal 1100 and transmits the same to the message processor 1162.

The message processor 1162 analyzes or interprets the syntax of the information or the message received from the receiver 1165. In particular, the message processor 1162 may analyze or interpret a message or information in a format as shown in Tables 1 to 7 above. For example, the message processor 1162 may check the mobility of the terminal 1100 by analyzing the syntax of the mobility indicator. The message processor 1162 informs each layer of the base station 1150 to perform the indication of each information or message by the base station 1150. Each layer that is instructed by the message processor 1162 may perform a function according to the instruction. For example, in the light of the mobility indicator, when the mobility of the terminal 1100 = medium speed, the message processing unit 1111 informs the parameter changing unit 1161, and the parameter changing unit 1161 determines an RRC related parameter, for example. DRX related parameters can be changed.

For example, the parameter change unit 1161 may adjust, change, or reconfigure the DRX cycle in consideration of a handover failure due to radio link failure (RLF) in the case of a high speed terminal. For example, the parameter changer 1161 may change the long-term DRX cycle into small periods. Alternatively, the parameter changing unit 1161 may change the long term DRX cycle into a short term DRX cycle. If only long-term DRX cycles are configured, short-term DRX cycles can also be configured simultaneously. While the long DRX cycle is running, the DRX configuration can be changed to increase the DRX inactivity interval. If the long-term DRX cycle before the change was sf = 160, then the change may consist of a longer cycle such as sf = 40 or the like.

As another example, the parameter changer 1161 may configure or reconfigure the DRX related parameters to reduce battery consumption as much as possible according to the mobility indicator received from the message processor 1162.

As another example, the parameter changer 1161 may configure or reconfigure DRX related parameters to reduce the traffic transmission delay as much as possible with reference to the mobility indicator.

As another example, the parameter changer 1161 may configure or reconfigure a connection release timer, which is a timer for maintaining the connection of the terminal 1100 according to the mobility indicator. For example, in the case of a high speed terminal, the parameter changing unit 1161 may configure the connection release timer to be relatively small so that the high speed terminal may quickly change from an RRC connected state to an RRC idle state. Alternatively, in the case of a low speed terminal, the parameter change unit 1161 may configure the connection release timer to be relatively large so that the low speed terminal changes to the RRC idle state after a longer time in the RRC connection state.

The parameter changer 1161 transfers the changed or reconfigured RRC related parameter to the message processor 1162. The message processor 1162 generates an RRC connection reconfiguration message including the reconfigured RRC related parameters and sends the generated RRC connection reconfiguration message to the transmitter 1155. The transmitter 1155 transmits an RRC connection reconfiguration message to the terminal 1100. For example, when the DRX related parameter is included in the RRC connection reconfiguration message, the RRC connection reconfiguration message may include a syntax as shown in Table 1 above.

On the other hand, the message processing unit 1162 is an assistant information for the interference avoidance for In-device coexistence (IDC) of the terminal 1100, assistance information related to the heterogeneous network (Hetnet), and MBMS-related System information indicating whether the base station can receive at least one of the auxiliary information is generated, and the transmitter 1155 transmits the system information to the terminal 1100.

The foregoing description is merely illustrative of the technical idea of the present invention and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas falling within the scope of the same shall be construed as falling within the scope of the present invention.

Claims (17)

In the mobility support method of the terminal performed by a terminal,
Checking the mobility of the terminal based on the number of cell changes;
Transmitting a mobility index indicating a mobility of the checked terminal to a base station;
Receiving from the base station an RRC connection reconfiguration message including parameters of a radio resource control (RRC) layer reconfigured by the base station based on the mobility indicator;
And configuring the parameters of the RRC layer in the terminal. The method of claim 1,
And receiving, from the base station, mobility support information indicating that the base station supports or permits mobility of the terminal. 3. The method of claim 2,
The mobility support information is included in an RRC connection setup message and received, and the mobility indicator is included in an RRC connection setup complete message and transmitted. The method of claim 1, wherein the mobility of the terminal,
If the number of cell changes is greater than or equal to a threshold number, it is checked at high speed.
And checking at a low speed when the number of cell changes is less than a threshold number. In the mobility support method performed by a base station,
Receiving a mobility index indicating the mobility of the terminal;
Reconfiguring parameters of a radio resource control (RRC) layer set up in the terminal using the mobility indicator;
And transmitting an RRC connection reconfiguration message including parameters of the reconfigured RRC layer to the terminal. The method of claim 5, wherein
And transmitting, to the terminal, mobility support information indicating that the base station supports or permits mobility of the terminal. The method according to claim 6,
The mobility support information is included in an RRC connection setup message and transmitted, and the mobility indicator is received in an RRC connection setup complete message. The method of claim 5, wherein the mobility of the terminal,
If the number of cell changes is greater than or equal to a threshold number, it is checked at high speed.
And checking at a low speed when the number of cell changes is less than a threshold number. In the terminal for transmitting the mobility indicator,
A mobility checker that checks mobility of the terminal based on the number of cell changes;
A transmitter for transmitting a mobility index indicating a mobility of the checked terminal to a base station;
A receiver configured to receive an RRC connection reconfiguration message from the base station, the RRC connection reconfiguration message including parameters of a radio resource control (RRC) layer reconfigured by the base station based on the mobility indicator; And
And a message processing unit configured to configure parameters of the RRC layer in the terminal. The method of claim 9,
The receiving unit further comprises receiving from the base station mobility support information (mobility support information) indicating that the base station supports or allows the mobility of the terminal. 11. The method of claim 10,
The receiving unit receives the mobility support information through an RRC connection setup message,
The transmitter is characterized in that for transmitting the mobility indicator through the RRC connection setup complete message, the terminal. The method of claim 9, wherein the mobility check unit,
If the cell change count is greater than or equal to a threshold number, the mobility of the terminal is checked at high speed;
And checking the mobility of the terminal at a low speed when the number of cell changes is less than a threshold number. In the base station that supports the mobility (mobility) of the terminal,
A receiver configured to receive a mobility index indicating mobility of the terminal;
A parameter changer configured to reconfigure parameters of a radio resource control (RRC) layer set up in the terminal by using the mobility indicator;
A message processor configured to generate an RRC connection reconfiguration message including the reconfigured RRC layer parameters; And
And a transmitter configured to transmit the RRC connection reconfiguration message to the terminal. The method of claim 13, wherein the transmission unit,
And transmitting, to the terminal, mobility support information indicating that the base station supports or permits mobility of the terminal. 15. The method of claim 14,
The transmitter transmits the mobility support information to the terminal through an RRC connection setup message.
The receiver, characterized in that for receiving the mobility indicator from the terminal via a RRC connection setup complete message, the base station. The method of claim 13,
The transmitter is characterized in that for transmitting the mobility support information to the terminal through system information (system information), the base station. The method of claim 13,
The message processor may include at least one of assistant information for interference avoidance for in-device coexistence (IDC), heterogeneous network-related assistance information, and MBMS-related assistance information of the terminal. Generate system information indicating whether the base station can receive,
The transmitter is characterized in that for transmitting the system information to the terminal.

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